tests: Remove incorrect check in "ovn -- external logical port"

This check passed because it checked the exit status of "wc -l", which
always succeeds.  It meant to check what "wc -l" output, but if it's
fixed to do that, then the test fails because it's checking something
that's wrong.  Thus, this commit just removes the check.

Signed-off-by: Ben Pfaff <blp@ovn.org>

tests/ovn.at

@@ -14518,11 +14518,6 @@ ovn-nbctl ha-chassis-group-add-chassis hagrp1 hv1 30
 
 hagrp1_uuid=`ovn-nbctl --bare --columns _uuid find ha_chassis_group name="hagrp1"`
 
-# There should be 1 HA_Chassis rows with chassis sets
-OVS_WAIT_UNTIL([ovn-sbctl list ha_chassis | grep chassis | awk '{print $3}' \
-| grep '-' | wc -l ], [0], [1
-])
-
 as hv1
 ovs-vsctl add-br br-phys
 ovn_attach n1 br-phys 192.168.0.1